In 1974, the Supreme Court of Iran brought foreign currency into the category of money and made the delay in its payment subject to the 12% rate of Damages for late payment stipulated in Article 719 of the Civil Procedure code approved in 1939. In this article, the mentioned Unification Judgment Decision has been analyzed in a descriptive and analytical way, and by examining the issue, it seems that, considering the difference between currency and money, the Supreme Court has taken a wrong path, because, currency is considered as the goods in domestic legal relations and it is exchanged for money. People's different goals in acquiring currency and its use are also different from using money. As a result, applying a fixed rate for late payment does not entail applying the same rate for currency. In the current situation, the legislator that it is confused the issue of Damages with reduction in the value of money, the Unification Judgment Decision has been criticized is invalid based on abrogation of article 719 and the non-provide its provisions in the new civil procedure code and especially because in the new code, the official inflation rate and price change index for The assessment of the responsibility for reduction in the value of money has been approved on the fact that it is only "calculable" in terms of money. This does not mean that no damages can be paid for the delay in the payment of the currency, but it seems like the Damages for late payment of money, the provision can be claimed by proving the legal conditions for claiming damages.